Small microbes almost killed all life on Earth, study suggests

Tiny microbes on the bottom of the ocean floor may have been responsible for the largest extinction event our planet has ever seen, according to a new study.

These microbes of death were so small, that 1 billion of them could fit in a thimble-full of ocean sediment, and yet, they were almost responsible for killing off all the life on our planet, the scientists suggest.

The end-Permian extinction was the most catastrophic mass extinction the Earth has ever seen. It started roughly 252 million years ago --long before the dinosaurs-- and it continued for 20,000 years. By the time it was over, nearly 90% of all life on Earth had been destroyed, the scientists say.